1. Field of the Invention
The invention relates to covers in a continuous strip for correspondence or for the distribution of confidential information.
2. Description of the Prior Art
It is known to manufacture wads or packets of continuous sheets folded accordion-wise of which each flap constitutes a single cover. These products to which the English name of "mailers" is generally given enable production on a printing machine such as the printer of a computer, of electro-accounting equipment, or the like, the lower sheet of the packet is intended to form for each of the flaps of the accordion fold, that is to say for each of the unit covers the back of the envelope of the cover concerned, whilst the upper sheet forms the faces of the envelopes. All the intermediate sheets are intended to constitute inner documents or inserts of each of the covers. According to known arrangements (carboned areas, chemical papers or self-reproducing elements possibly in zones, etc.) the impression of the printer is brought back selectively on certain of the sheets, hence on certain of the inner documents whilst non-personalized endorsements, that is to say identical for all of the covers are printed on one or several sheets before their assembly. The packet almost always includes in addition a covering strip, called the archive or control strip, which covers the upper sheet.
Apart from the control strip, all the sheets of the packet are united by glueing along their natural edges, with the exception, possibly, of certain intermediate sheets which can be narrower than the others and in this case packaged along one only of their lateral edges. Each of the flaps or covers is sealed at the head and at the foot by transverse threads of glue. Mostly these threads unite the upper and lower sheets through transverse cutouts formed on all the intermediate sheets.
Detachable lines of perforation and/or rupture initiation enable the opening of the covers by the addresses and the extraction of the inner documents.
Lastly, on each of its lateral sides, the packet is provided with drive perforations situated on a detachable marginal area. These perforations serve for driving the packet in the printing machine and then in the unifying device, but they also serve for driving each of the sheets in the packet assembly machine (called an assembler or collator) and they pre-exist on each of said sheets (on a single side for the narrower sheets).
After the passage into the printer the package is brought to a unifying device where after removal of the possible cover strip, the covers are separated from one another along accordion fold lines, either by rupture by pulling, or by cutting (guillotine). Very often at the input of the device longitudinal cutting trimmers detach the marginal zones bearing the drive perforations, but this arrangement is not obligatory.
In the collator which effects the manufacture of the assembly, each continuous sheet provided with its marginal drive perforations unrolls from a reel and follows a particular circuit in the course of which it passes through a succession of work stations where the necessary fashioning is carried out (weakening lines for the accordion folding, lines of detachable perforations or rupture initiation, cutouts, glueing, etc.).
In spite of the precautions taken and the safety devices (presence detectors), when a reel is emptied a gap can occur and some of the flaps of the package can be devoid of the sheet corresponding to said reel. The same accident can occur each time that a strip is restored into circulation, as a result of a breakage for example. This absence is undetectable in the course of subsequent processing when it relates to an intermediate sheet and the corresponding covers arrive at their addressees with an inner document lacking.
This lack is of somewhat less importance when it relates to commonplace documents, but it can be serious when it relates, for example, to an invoice, a pay check an acknowledgement of receipt, etc., and even very serious in the case of a summons, a cheque or other document whose "actual" dispatch must be checked. That is a serious drawback of the present "mailers".
In the case of a cheque or other document numbered in advance (by printing or by stamping) before the packaging of the continuous sheets, the "mailers" at present known have another drawback. For cheques for example, the bank drawn upon attributes to its customer a certain sequence of numbers within a given series, then another sequence in another series, etc. The customer himself has the cheques printed with their numbers (order and series) and must inform the bank of the cheques issued generally in the following form:
______________________________________ Date . . . . . . . . , check series X n.sup..degree.. . . . . . . . . to . . . . . . . . . . check series Y n.sup..degree.. . . . . . . . . to . . . . . . . . . . ______________________________________
It is hence necessary for the user of the "mailer" to preserve a visible trace of the numbers of the checks dispatched although the latter (inner documents of covers sealed in manufacture) cannot be read after their passage in the printer. The only present means of marking consists of printing these numbers on a cover or control strip at the same time as on the intermediate continuous sheet intended to form the sequence of checks. One has thus on the control strip the list of numbers of the cheques it has used and sent out, but on condition that, on the one hand, the marking of the cover strip and the continuous sheet of cheques be correct at the moment of assembly into a packet and that, on the other hand, an accidental gap does not occur (as above) in the intermediate sheet.
It is an object of the "mailer" according to the invention to overcome these drawbacks.
Other objects and advantages of the invention will become apparent on reading the description which follows.